A large body of literature exists regarding the effects of dietary protein on blood lipids in adult humans and animals; however, little is known of the action that protein source may have on cholesterol levels in infants. The research of this thesis addresses the following questions; (1) do infant formula proteins affect blood lipids in young animals, (2) is there a permanent response of protein consumed during childhood on adult cholesterol metabolism, and (3) what mechanisms mediate the blood lipid response to dietary protein? In a study which examined the effects of varying casein and whey proteins fed to rabbits during post-weaning, it was determined that a diet of 40% casein and 60% whey protein elevated blood lipids compared to consumption of greater proportions of casein (p $